The purpose of this research is to study grammatical aspects of aphasic language, and test and improve on existing analyses of the difficulties aphasic patients have in synaptic processing. This investigation is important because we have, at this point, a significant body of evidence indicating that in some aphasias (and potentially in a majority of the syndromes) aspects of the deficit are highly selective from a grammatical viewpoint, an observation which has important implications for theories of brain/language relations, and for theories of language structure, processing, and acquisition. Our studies will focus on aphasic abilities in highly complex syntactic structures. We will take, as our point of departure, the Trace-Deletion Hyothesis. The TDH draws a clear line between impaired and preserved syntactic abilities, claiming that for agrammatic Broca's aphasics, at least, structures containing traces of syntactic movement are deleted. A variety of studies in several languages have put this claim to test, helping revising and refining it . We plan to further extend the data base in new directions that will have consequences to theoretical as well as clinical diagnostic issues, using the TDH as a guideline. Specifically, we will be studying dependency relations of various sorts: First, we will be testing aphasic comprehension abilities, where the manipulated variable will be sentence structure, and more specifically trace/antecedent relations that hold in structures containing quantifies and questions. Second, we will investigate their abilities to make acceptability judgments in structures containing traces, to examine their sensitivity to traces in grammatical representation. Third, we will be looking a intrasential dependencies which do not contain traces (pronouns and their antecedents in discourse and VP-ellipsis), in order to tease apart "intrasentential dependency" from "trace of movement". In every instance, we will be comparing our results to findings from other aspects of language, namely it processing and acquisition. We thus hope to achieve two goals: First we seek to continue the development of fine-grained experimental procedures to discover the deficit in aphasia in its entirety, and improve existing diagnostic methods. Second, we seek to compare our results with other domains of inquiry in psycholinguistics, and to continue a line of research that has recently shown resurgence, namely, the relation between the acquisition and breakdown of language.